Mahonia aquifolim extract, extraction process and pharmaceutical composition containing the same

ABSTRACT

The present invention provides a skin treatment composition comprising a  Mahonia aquifolium  extract in a liposome delivery system. The  Mahonia aquifolium  extract is present in the skin treatment composition in a range of from 5% to 20% by weight of the total composition. The skin treatment composition is particularly effective in the treatment of psoriasis, eczema and other dry skin conditions. The invention further provides a process for obtaining an extract of  Mahonia aquifolium.

FIELD OF THE INVENTION

The present invention is directed to a Mahonia aquifolium extract, aprocess for obtaining a concentrated form of the extract using a newextraction process and a pharmaceutical composition containing theextract. The pharmaceutical composition is a particularly effectivetreatment for psoriasis, eczema, dermatitis and other dry skinconditions.

BACKGROUND OF THE INVENTION

Psoriasis is a chronic skin disease that is characterized by scaling andinflammation of the skin. The scaling occurs when the cells in the outerlayer of the skin reproduce faster than normal and pile up on the skin'ssurface. Psoriasis affects about 1.5% to 2% of the North Americanpopulation. It occurs in all age groups and affects men and womenequally. People affected by psoriasis suffer from discomfort, restrictedjoint motion and emotional distress. About 10% of people suffering frompsoriasis have joint inflammation that produces symptoms similar toarthritis.

When psoriasis develops, patches of skin thicken, redden and becomecovered with silvery scales. These patches are generally referred to asplaques. The plaques are usually itchy and can burn. Psoriasis mostoften occurs on the elbows, knees, scalp, lower back, face, palms andsoles of the feet.

A variety of treatments and methods have been used over the yearsincluding the topical application of corticosteroids, calcipotriene,coal tar, etc. Bath solutions and general moisturizers have beenutilized by some patients. Sunlight and ultraviolet light treatmentshave also been used. In some instances systemic treatment usingprescribed medicines taken internally are needed. Drugs taken internallyinclude retinoids, methotrexate, hydroxyurea and antibiotics.

Each of these treatments has its benefits and drawbacks. In manyinstances, patients develop a tolerance to the treatment and thetreatment becomes much less effective. The inventors have sought atreatment suitable for a variety of patients that overcomes thedrawbacks noted above.

Mahonia aquifolium was originally found in the Pacific Northwest andBritish Columbia where it has been used for the treatment of psoriasisand eczema by Native North Americans for many centuries. It is anevergreen shrub that belongs to the Berberidaceae family.

The root and bark of the Mahonia aquifolium plant are known to containisoquinoline alkaloids that include berberine, palmatine, berbamine,oxyacanthine, jatrorrhizine, bervulcine, magnoflorine and columbamine.These alkaloids are thought to be the active constituents of the plantsas many of them have shown strong in vitro anti-microbial andanti-fungal activity.

Mahonia aquifolium may have several mechanisms of action in thetreatment and management of psoriasis and other inflammatory conditions.Berberine and related alkaloids as noted above reversibly intercalate inDNA hindering replication and transcription. Mahonia extract containsisoquinoline alkaloids as outlined above. Isoquinoline has beenidentified as a component of coal tar which causes interfollicularregions of parakeratotic stratum corneum in mouse tail epidermis tobecome orthokeratotic, with concomitant production of a granular layer.In this respect, isoquinoline behaves similarly to coal tar and theisoquinolines may contribute to the anti-psoriatic activity of coal tar.Alkaloids isolated from the extract demonstrate anti-proliferationactivity on keratinocytes. Hyper proliferation of keratinocytes is amajor symptom of psoriasis and so controlling this activity will assistin the treatment of psoriasis. Lipoxygenase inhibition is stronglycorrelated with the lipid antioxidant effect of the protoberberinealkaloids, perhaps by reducing lipid hydroperoxide substrateaccumulation. Mahonia is a moderate inhibitor of LTB-4 (a leukotrienewhich is believed to mediate inflammation) and5-hydroxy-eicosatetraenoic acid (5-HETE) with an IC-50 in the same orderof magnitude as anthralin. IC-50 refers to the concentration at which50% inhibition occurs.

Mahonia aquifolium extract is also a very potent inhibitor of lipidperoxidation. Individual alkaloids isolated from the extract demonstrateanti-inflammatory activity by inhibiting the action of lipoxygenase.Oxidation products resulting from the action of lipoxygenase are knownto be mediators of inflammation in other biological systems. Theinhibitory effect of Mahonia aquifolium on lipid peroxidation contrastswith anthralin, which slightly stimulates lipid peroxidation. Thisdifference may explain why Mahonia aquifolium extract reducesirritation.

DETAILED DESCRIPTION OF THE INVENTION

The Mahonia aquifolium extract of the present invention is obtained in ahighly concentrated form using an extraction process as detailed below.The regents used in the extraction process are water, alcohol and crudedried Mahonia aquifolium.

The crude dried Mahonia aquifolium is obtained from dried bark and twigsof plants from the Mahonia aquifolium (Berberidaceae) family. Suchplants include plants of the barberry family, for example, Oregonhollygrape.

The reagents are loaded into a stainless steel reactor vessel. Thevessel is clamped shut. Pressure of 3 to 6 psi (volume dependent) isapplied to the reactor vessel and the reagent mixture is heated to atemperature not higher than 50° C., preferably about 40° C., whilemixing the contents with an internal counter-rotating agitating mixer.When the mixture reaches 40° C. an internal grinding mixer is engagedand the mixture is processed at a speed of about 3000 rpm (revolutionsper minute) in combination with the internal counter-rotating mixer forthree hours. The mixture is left under pressure of 3 to 6 psi in thereactor and is allowed to cool for not less than 24 hours.

After the 24 hours has elapsed the internal grinding mixer is againengaged and the mixture is processed at a speed of about 3000 rpm incombination with the internal counter-rotating mixer for three hours.The mixture is left under pressure of about 3 to 6 psi in the reactorfor not less than 24 hours.

After the second 24 hour period, the internal grinding mixer is againengaged and the mixture is processed at a speed of about 3000 rpm incombination with the internal counter-rotating mixer for three hours.The mixture is then left under pressure of about 3 to 6 psi in thereactor for a minimum of 24 hours.

After the third 24 hour period, the pressure is released in the reactorand the reagent mixture is filtered through a coarse mesh filter andthen through a 5 micron filter. The mixture is then placed under vacuumand heated to a minimum of 40° C. but not more than 50° C. while mixingto reduce and remove the solvents until the mixture is approximately 6%of its original volume. The resultant product is re-filtered through a1-micron filter.

This extraction process yields a finished Mahonia aquifolium extractwith a concentration of approximately 1.5 mg/ml berberine alkaloid. Atypical alcohol based extraction process will yield a finished extractwith a concentration of approximately 0.09 mg/ml berberine alkaloid.

The product obtained from this extraction process is then utilized toprepare a pharmaceutical composition suitable for use in the treatmentof psoriasis and other skin ailments and diseases.

The pharmaceutical composition is prepared for use by combining theMahonia aquifolium extract in a liposome delivery system.

Liposomes are microscopic spherical vesicles that form whenphospholipids are hydrated. Recently, liposomes have been utilized andevaluated as delivery systems for drugs, vitamins and cosmeticmaterials. They can be custom designed for almost any use by varying thelipid content, size, surface charge and method of preparation. As theliposome wall is very similar, physiologically, to the material of cellmembranes, they are particularly suitable for the delivery of productsfor application to the skin. When a pharmaceutical or cosmeticcontaining liposomes is applied to the skin, the liposomes are depositedon the skin and begin to merge with the cellular membranes. Theliposomes release the active material into the cells and as a result thedelivery of the active material is very specific. The liposome deliverysystem can be designed to release the active materials under a varietyof conditions, for example, slow release, fast release, bilayercompositions, temperature dependent release, pH-dependent release, etc.

A preferred liposome delivery system for use in the pharmaceuticalcomposition of the present invention is the Novasome® technology.Novasome lipid vesicles are comprised of molecules that possess bothhydrophilic and hydrophobic properties (i.e. amphiphiles). The Novasomevesicles are made up of one or more lipid membranes or bilayers(generally 5 to 7) that surround a larger core. Each membrane iscomposed of amphiphiles in a bilayer array.

The core accounts for most of the vesicle volume, providing a highcarrying capacity for water-soluble and water-immiscible substances. TheNovasome bilayers are not in perfect array and contain vacancies(channels) through which encapsulated components can travel.Encapsulated components travel within and between each bilayer via aseries of random jumps which causes lateral movement of the vacancies inthe bilayer.

An active ingredient is contained in the core and can pass from the corethrough the bilayer. A sustained release mechanism is provided by thestructure of the Novasome vesicles so a continuous and controlledrelease of the active ingredient can be achieved. As the activeingredient is entrapped within the core in a more protected manner priorto use the storage stability and the stability of the active ingredientis improved. This provides for more efficient and effective delivery ofthe active ingredient.

The pharmaceutical composition is prepared by combining Mahoniaaquifolium extract in a concentration of approximately 5% to 20% byweight of the total composition in a liposome delivery system. Theliposome delivery system detailed just above is one preferred deliverysystem. Preferred compositions have a concentration of Mahoniaaquifolium of between 5% and 10% by weight of the total composition.This will provide the composition with a minimum of 0.712% berberine.

The remainder of the composition comprises typical pharmaceuticallyacceptable components, for example, diluents, adjuvants, etc.

The composition is utilized in a topical application form and is applieddirectly to the affected area. The composition can be in the form of alotion or cream.

Three typical formulations are detailed below. The percent by weightnoted of each component is a percent by weight of the total composition.The Mahonia aquifolium extract is in the liposome delivery system.Component percent by weight Lotion DI water 51.04 Mahonia extract 10.00transcutol 8.00 glyceryl dilaurate 8.00 glyceryl monostearate 4.50 96%glycerin 3.41 diisopropyl adipate 3.00 cyclomethicone 2.50 dimethicone2.00 octyl palmitate 1.40 C₁₂₋₁₅ alcohol lactate 1.00 chamomile extract1.00 stearoxydimethicone 0.70 cholesterol 0.50 Polysorbate 80 ™ 0.50cetearyl glucoside 0.50 cetyl alcohol 0.50 green tea extract 0.50phenoxyethanol 0.40 Methylparaben ™ 0.20 xanthan gum 0.15 disodium EDTA0.10 vitamin E acetate 0.10 Cream DI water 44.95 Mahonia extract 10.00transcutol 10.00 glyceryl dilaurate 8.00 glyceryl monostearate 4.50 96%glycerin 3.41 cyclomethicone 3.00 dimethicone 2.50 cetearyl glucoside1.50 PEG-150 monstearate 1.50 diisopropyl adipate 1.50stearoxydimethicone 1.00 C₁₂₋₁₅ alcohol lactate 1.00 ethyl oleate 1.00diisopropyl sebacate 1.00 cetyl alcohol 1.00 chamomile extract 1.00Sepigel 305 ™ 1.00 green tea extract 0.50 cholesterol 0.50phenoxyethanol 0.40 xanthan gum 0.30 Methylparaben 0.20 disodium EDTA0.10 alpha toccopherol acetate 0.10 citric acid 0.04 Scalp TherapyComposition DI water 67.34 Mahonia extract 10.00 glyceryl monostearate4.50 chamomile extract 3.00 propylene glycol 2.50 avocado unsaponifiable2.00 Quaterium 22 ™ 2.00 cyclomethicone 1.40 behentrimonium methosulfate1.00 cetearyl alcohol 1.00 aloe vera powder 1.00 green tea extract 1.00wheat germ oil 1.00 stearyl alcohol 0.70 triethanolamine 0.66 Quaterium26 ™ 0.50 Methylparaben 0.20 DMDM hydantoin 0.20

In clinical studies and trials, as detailed below, the beneficialeffects of the composition of the present invention were noted.

In one trial psoriatic patients having mild to moderate psoriasisapplied the composition of the present invention to one half of theaffected area. To the other side of the affected area the patientsapplied a plain vehicle cream (the cream utilized to prepare thecomposition of the present invention). The compositions were appliedtwice a day for four weeks. All eleven patients were compliant andfinished the four week course of the study. Nine patients improved, oneremained the same throughout the treatment but was less pruritic and oneimproved on the plain vehicle cream side only. Of the nine patients thatimproved, one patient cleared on both sides, one patient improved onboth sides equally, one patient improved slightly on the side utilizingthe composition of the present invention and six patients weredefinitely improved on the side utilizing the composition of the presentinvention.

In another study low concentrations of Mahonia aquifolium extract in acream base demonstrated that the preparation was safe and well toleratedwhen applied to plaques of psoriasis.

A second study was initiated to examine the safety, tolerability andefficacy of higher concentrations of Mahonia aquifolium extract in 33patients with a variety of types of psoriasis and 8 patients witheczema. The study was an observational study.

The patient population included a wide range of age groups and includedboth sexes. Treatments prior to the start of the application of Mahoniaaquifolium extract ranged from no treatment to topical corticosteroids,Dovonex™, ultraviolet light and methotrexate.

Mahonia extract and vehicle treated lesions were photographed prior totreatment and throughout the study. The target lesions were scored forscaling, thickness and redness. In almost all cases scaling was thefirst symptom to improve. In many cases improvement was noted after thefirst week of treatment. The thickness of the plaques generally declinedsubstantially over 2 to 4 weeks. Redness improved most gradually. Thisis common for most psoriasis treatments.

In some cases the methotrexate and/or ultraviolet light treatmentcontinued when the application of Mahonia extract started. The Mahoniaextract did not cause any adverse interactions with these treatments andthere was no evidence of photosensitivity or phototoxicity. Mahoniacream may be a complementary treatment. There was no clinical evidencethat the creams being tested blocked or interfered with ultravioletlight.

The Mahonia cream was enthusiastically accepted by all the patients andcompliance with and adherence to the experimental protocol was good. Inall cases of both psoriasis and eczema the side treated with Mahoniacream did as well as or better than the side treated with the vehiclecream alone.

1. A skin treatment composition comprising an extract of Mahoniaaquifolium in a liposome delivery system.
 2. A skin treatmentcomposition as claimed in claim 1 wherein the extract of Mahoniaaquifolium is present in a concentration of from 5% t 20% by weight ofthe total composition.
 3. A skin treatment composition as claimed inclaim 1 wherein the extract of Mahonia aquifolium is present in aconcentration of 10% by weight of the total composition.
 4. A processfor obtaining an extract of Mahonia aquifolium comprising the steps of:(a) applying heat and pressure to a mixture of water, alcohol and crudedried Mahonia aquifolium ; (b) stirring the mixture; (c) processing themixture at a speed of about 3000 rpm for about three hours; (d) allowingthe mixture to cool under pressure for at least 24 hours; (e) repeatingthe last two steps at least twice more; (f) releasing the pressure; (g)placing the mixture under vacuum with heating and mixing to reduce andremove the alcohol and water to obtain a mixture of approximately 6% byvolume; and (h) filtering the resulting mixture to obtain the extract ofMahonia aquifolium.
 5. The method of claim 4 wherein in step (a) themixture is heated to a temperature of not higher than 50° C.
 6. Themethod of claim 4 wherein in step (a) the mixture is heated to atemperature of 40° C.
 7. The method of claim 4 wherein the pressure isin a range of about 3 to 6 psi.
 8. An extract of Mahonia aquifoliumobtained by the process of claim
 4. 9. Method of treating psoriasis,eczema and other dry skin conditions by applying the skin treatmentcomposition of claim 1.